In some applications, a banknote validator feeds accepted banknotes to a bin or storage container where they are loosely stored. For example, some vending machines include a banknote validator so that paper currency can be accepted for the purchase of expensive items for which it is onerous for a customer to pay in coins. Currency which is accepted is fed from the outlet of the currency validator to a cashbox where it is loosely stored until collected by the vending machine's owner. In other vending machines, space may be at a greater premium or for other reasons it may be highly desirable to compactly and neatly stack accepted currency rather than loosely storing it.
As a result, various stacker arrangements have been previously developed. See, for example, U.S. Pat. No. 4,050,562 assigned to the assignee of the present application, and U.S. Pat. Nos. 4,011,931, 4,000,892, 3,977,669, 3,917,260, 3,851,744, 3,788,333, 3,765,523, 3,655,186 and 3,222,057. Two commercially used stacker arrangements are briefly described below. In the first, a banknote which has been accepted by a validator is allowed to fall under the influence of gravity into a first compartment of a stacker, a pusher unit then pushes the fallen banknote into a stack in a storage compartment of the stacker. This arrangement does not maintain positive control over a banknote. As a result, jams and poorly stacked banknotes are likely to occur more frequently than is desirable. Such less than optimal operation is more frequently observed where worn, old banknotes are being stacked.
In a second commercial arrangement, a stacker is included as part of an integral validator-stacker unit. In this unit, a common drive belt provides for positive control of a banknote's movement from insertion until it is stacked. This integral arrangement is mechanically complex and lacks the flexibility to make it readily adaptable to meet a wide range of different applications. This second arrangement limits stacking to a single direction, and does not allow the operation of its validator without its stacker.